Manufacture of non-conducting coverings, blocks, and slabs.



i ing body to unite chemically with the asbesto. 774,947. PatentedNovember 15, 1904.

"UNITED STATES PATENT OFFICE.

HENRY O OLBECK MICHELL, OF LONDON, ENGLAND.

MANUFACTURE OF NON-CONDllCTlNG COVERINGS, BLOCKS, AND SLABS.

dated November 15, 1904.

(No model.)

srncmrcamrox forming part of Letters Patent No. 774,947,

Application filed liova mber 27, 1903. Serial No. 182,888.

To all whom/7J1; may concern:

Be it known that I, HENRY CoLBEoK MICH- ELL, a subject of the King ofGreat Britain and Ireland, residing in the city of London, England, haveinvented an ImprbvedfManufacture of Non-Conducting Coverings, Blocks,and Slabs, of which the following is a specification.

This invention has reference to an improved manufacture of that kind ofnon-conducting coverings, blocks, and slabs suitable for coveringsteam-pipes, boilers, and the like to protect them from loss of heat byradiation and for other purposes where it is desired to prevent thepassage or flow of heat that are composed of or contain asbestos and asilicious binding agent, such as silicate of soda, with or withoutaddition of other ingredients; and it has for its object to producenon-conducting coverings, blocks, orv slabs of the kind mentioned thatshall be more durable and efficient in use than those heretoforeproduced. For this purpose in the manufacture of nonconductingcoverings, blocks, and slabs composed'of or containing asbestos and afusible silicious binding agentfor example, silicate of soda, clay, andthe like-such coverings, blocks, or slabs (hereinafter, including theclaims, referred to generally as non-conducting bodies) after beingmolded or formed to shape and dried, as heretofore, are subjected to ahigh temperature in sucha manner as to cause the silicious binding agentused to unite or combine. with the asbestos in the non-conducting bodyin such a way as to render the latter very durable and efficient Theheating may conveniently be effected by firing in a kiln at atemperature,say,- for example, up to about 1,000 centigrade, (onethousand degrees centigrade;) so as to fuse, vitrify, or cause thesilicate of soda in the non-conductmixed'asbestos and silicate of soda,and firing the same in a kiln, or the asbestos and solution of silicateof soda may be intimately mixed together in the mass, as by hand or by amixing-machine, then molded to shape or spread out in layers and thendried and fired.

The solution. of silicate of soda may be of commerce and be used in suchproportion with the asbestos as to form therewith a wet mass having theconsistency of, say, ordinary wet mortar, so that the result of heatingthe mixture, as set forth, will be to cause the asbestos by the fusionor vitrification of the silicate to adhere firmly together withoutcausing the non-conducting body to lose its shape.- Any excess ofsilicate of soda that may be present in the body when formed to shapewill be caused to exude therefrom during the preliminary drying thereofby heat.

The interiors of non-cond ucting bodies made as described may be chargedwith non-conducting material of various kindsfor example, mica and lightporous or open filling material of the kind described in thespecification of Letters Patent of the United States granted to me, No.7 32,207

Although in the example given 1,000 centigrade has been mentioned as asuitable temperature to which a non-conducting body according to thisinvention might be heated, I do not limit myself. to such temperature,as in some cases lower or higher temperatures might'with reasonablelimits be advantageously employed so of the ingredients is effected.

Non-conducting bodies may be produced as hereinbefore described withclose and durable outer crusts or shells inclosing inner portionsconsisting of light porous or open filling ma: terial of the kindhereinbefore referred to or may be formed of an intimate mixture ofasbestos, filling material, a binding agent, and

tos and form a compound silicate therewith.

a non-hygroscopic substance and molded to The non-conducting bodies maybe built up and formed to shape in the manner heretofore usualas,'forexample, by spreading the asbestos in a loose, broken-up, or ,fluifycondition in or. on a suitable support or mold, distributing a solutionof silicate of soda over the, layer of asbestos, drying the layerof.ceous coverings, blocks, or slabs inmy said former specification. Whensuch open or filling material consists wholly or partly of matter thatwill be charged or burned out during the subsequent heating of thenon-conthe strength Twaddell) ordinarily sold in long as the requisiteunion shape as described with reference to mica-'95 ducting body, theporosity and non-conductconducting bodies, which consists in forming ingproperties of the resulting product will an intimate mixture of asbestosandsilicate of I5 in many cases be enhanced. l Although the inventionhas been described to fuse the silicate and chemically unite the 5 withmore particular reference to non-conelements, and slow y cooling themass, whereducting bodies for preventing loss'of heat by by a dense hardvitreous product is obtained. radiation, it is obvious that such bodiesare Signed at London, England this 18th day' also applicable forpreventing absorption of of November, 1903. heatas, for example, in thecase of pipes to used for conveying cooled brine in refriger- HENRY P Lating apparatus. 7 I Witnesses: y 7

hat I claim is F. D. JAMESON, Theherein-described Inethodofmakingnon--H. RAND.

